Method for cleaning telephone switchboards



F. ACKERMAN 2,043,278

METHOD FOR CLEANING TELEPHONE SWITCHBOARDS Filed March 16, 1954 4 9 FIGl.

June 9, 1936.

By Att'y Patented June 9, 1.936

UNITED STATES aoiazrs mirnon Fon CLEANING 'rELErnoNE swrrcnnoannsFrankvAckerman, University City, Mo., assignor to Curtis ManufacturingCompany,

St. Louis,

Mo., a corporation of Missouri Application March 16, 1934, Serial No.715,803 l Claim. (01.15-269) Telephone switchboards are provided withnumerous minute and delicate contacts by means oi which the desiredcircuits are established. Particles of dust collect on these contacts,interfering with their proper functioning and resulting in noisytelephone operation.

It is the object of my invention to provide effective means for removingdust particles from such telephone contacts and collecting the dust soas to prevent its re-deposit upon the same or other contacts. In theaccompanying drawing, which illustrates one form of apparatus forcarrying out my invention, Figure 1 is an end elevation of a pair ofswitchboards to which my apparatus is applied; Figure 2 is a front viewof the dust collector, partly in elevation and partly in section on theline 2-2 of Figure 1; Figure 3 is a section taken on the line 3-3 ofFigure 2; and Figure 4 is a section taken on the line 4-4 of Figure 3.

In Figure l of the drawing I have shown two telephone switchboards 5 ofthe automatic type. This type of switchboard is provided with variousstyles of automatic switch devices conventionally illustrated at 6, theswitchboard being open both at the front and the rear to give access tothe switches. This construction also permits the use of an air blastnozzle I for detaching particles of dust from the switch contacts. Thenozzle I is connected by a exible hoset with a high pressure air supply(not shown).

Switchboards of this type are usually spaced about two feet apart tolpermit inspection of the switches. This spacing provides room for aport- 3" able dust collector, such as is used in conjunction with theair blast nozzle in carrying out my invention.

The vdust collector consists of a housing 9 mounted on casters iii so asto be readily moved between a pair of switchboards 5. Situated in thelower end of the housing are a pair of suction fans II which are drivenby an electric motor it positioned between them. The housing whichextends to the top oi the switchboards 5, is divided by partition wallsI3, perpendicular to the backs I4, and inclined walls I5 into a centralair passage I6, approximately T-shaped in cross section, and a pair oflateral air passages I1. The iront face of the passage I 6 is coveredwith porous lterlng material I8, and the outer sides of the passages I1,that is the ends of the housing, are covered by similar porous filteringmaterial I9; The filters I8 and I9 may each be formed of a single sheetof material. However, on account of the height of the device which inpractice is between eleven and t`welve feet, I prefer to apply theiilters in sections, as shown in the drawing. The action of the fans I Iis to draw air down through the central passage I6 and discharge itupwardly into the lateral passages I1. The air withdrawn from thepassageI6 is replaced by external atmosphere which can only enter through theiilter I8. As a result of this, a strong suction is produced over theentire front face of the iilter i8. To equalize this suction throughoutthe area, of the 1o lter, I provide a baille plate 2li positionedadjacent to but out of contact with the inner face of the filter I8.This plate is tapering in form, as shown in Figure 2, and extends fromthe bottom of the filter to a point near the top thereof. The baille l5plate is supported by cross-bars 2| having their ends secured to theinclined partition walls i5. Without the use of the baiiie plate thesuction would be greater at the lower part of the filter adjacent thefans.

In carrying out my method of cleaning telephone switchboards or panels,as they are usually designated, the dust collector is positionedadjacent one face of the panel, as shown in Figure 1,v to establish asuction zone adjacent the panel 25 equal in area to the filter I8. Thissuction zone is indicated by curved arrows in Figure l of the drawing.Dust is now dislodged from the switch contacts by means of a highpressure jet of air delivered from the nozzle i manipulated by a 33workman at the opposite side of the panel. The dislodged dust being inthe suction zone is carried to the lter, this action being assisted bythe disiodging jet itself which, as it is operated at the opposite sideof the panel, discharges air in 30 the same general direction as thecurrents of air forming the suction zone. The dust carried by these aircurrents is deposited either upon the face of the lter i8 or areimbedded in its substance. The air drawn from behind the filter I8 40 isdirected upwardly through the passages il and returned to the externalatmosphere through the lters I9. The object of the illters I9 istwofold; first, to remove particles of dust which may have penetratedthe iilter I8; and second, to secure a relatively gentle discharge ofair over a considerable area, thus avoiding violent disturbance of airin the room containing the panels such as would result from a directdischarge of air from the fans into the room. After an area of the panelequal to that of the filter I8 has been cleaned, the collector is movedforward a distance equal to the width of said iilter and the operationis repeated. i

Having fully described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

The method of dislodging dust from the contact surfaces of switches of atelephone switch panel oi' the type in which the spaces adjacent theswitches are in communication with the air of the room containing thepanel and preventing` redeposit ot said dust on said switches, whichcomprises dislodging the dust from the contact surfaces of the switchesby manipulating a jet of high velocity air against said contacts andsimultaneously acting upon a portion of the air of the room to maintainan unconiined zone of air currents oi' relatively low velocity embracingthe contacts being operated upon and of sumcient area that no dislodgeddust particles are projected out of said zone by the high velocity jetand said dust particles are conveyed by the air currents ot said lowvelocity zone, and directing the air oi the low velocity currents awayfrom the switch panel.

FRANK ACKERMAN.

